边界粘土层被科学家用来确定一个灭绝物种衰落的速度。
Boundary clay layers are used by scientists to determine the rate at which an extinct species declined.
答案可能是，现在火星上几乎所有的水都被锁在地表下的永久冻土层中，更多的水被包含在这个星球的极地冰帽中。
The answer may be that virtually all the water on Mars is now locked in the permafrost layer under the surface, with more contained in the planet's polar caps.
这次火山喷发在上层大气中留下了一个薄薄的尘土层。
The eruption has left a thin veil of dust in the upper atmosphere.
地质学家认为，这个具有流体化喷出物的陨石坑表明，在地表下几米深处有一层永久冻土层或水冰。
Geologists think that this fluidized ejecta crater indicates that a layer of permafrost, or water ice, lies just a few meters under the surface.
五吨的土会装满一辆小型自卸式卡车；若铺开在一英亩的土地上，它会形成不足一角硬币厚度的土层。
Five tons of soil would fill a small dump truck; if spread over an acre, it would make a layer slightly less than the thickness of a dime.
这个季节，我们发现的主要是粘土层。
接下来是人才的本土层次。
台地被风化侵蚀后的沙土层形成了陡峭的峡谷和悬崖。
Softer rock layers within the mesas eroded to form steep canyons and overhangs along their slopes.
几乎到处是冰——永冻土层——现在都在融化。
海滩上，有一个不规则的正在融化的永久冻土层。
地球土层根据深度的排列而得出了一个化学年表。
This holds a chemical chronology of the Earth laid out by depth.
“气候引爆点”的一个例子就是永久冻土层的融化。
An example of a tipping point is the thawing of the permafrost.
海冰和冻土层的出现很多年来帮助保护了北极障壁岛。
The presence of sea ice and of permafrost helps protect Arctic barrier islands for much of the year.
这个工作需要引入土层和沙层，然后用重机械把它们压制到一起。
The job entails bringing in layers of soil and sand, then compacting it with heavy machines.
多岩石的月球上土层非常薄，所以在机器下降的时候土会被吹走。
The layer of lunar dust on the rocky moon is thin, so was blown away from the landing area by the descent engines.
知道你的饮用水的来源——河流，湖泊或是你家的含水土层。
Know the source of your drinking water-the river, lake, or aquifer that supplies your home.
他们共同测绘了详细的地表图，一起击碎石块，监测大气，并探测土层。
Together, they have mapped the surface in unprecedented detail, cracked open rocks, sniffed the atmosphere and dug down into the soil.
随着植被覆盖面的消失，每次雨季都将更多的宝贵的表土层冲到湖里去。
With the tree cover gone, every rainy season sees more of the precious topsoil washed away into the lake.
劳克雷说，“鹭是通过慢慢移动来搅动底土层并找到食物的”。
"Herons do a shuffling behavior to stir up the substrate" and find food, said Lockley.
永久冻土层经过千万年的累积形成，其中包含了巨量的冻僵的有机物。
The permafrost contains immense amounts of frozen organic matter that have been accumulating for millennia.
去年，印度科学家的一项研究显示冻土层的消融速度比预期的要慢得多。
A study by Indian scientists last year found that the rate of glacial retreat was considerably slower than previously estimated.
华北平原大多是褐色土壤，土层深厚，农作物有小麦、玉米、谷子、棉花等。
The deep, brown topsoil of the North China Plain is planted with wheat, corn, millet, sorghum and cotton.
最主要的展品是在冻土层中完好保存的猛犸象骨架，它被发现于1999年。
But the main exhibit is the completely preserved in a piece of permafrost mammoth, which was found in 1999.
然后用紫外线通过露光模板的光孔照射到印刷台的粘土层，以此塑造出需要的模型图案。
This layer is exposed to ultraviolet light through a mask that represents the required pattern.
但是，在松软的土层上，长周期地震波的震动会被放大，可能使摩天大楼的摇摆更加剧烈。
But on soft soils, vibrations from long-period seismic waves are amplified, possibly exacerbating the swaying of skyscrapers.
因为这里是永久冻土层，没有泉流和水井。当地人只得锯开冰冻小河来获得饮用水。
Because of the permafrost there are no any springs and Wells here, so the locals have to saw the "drinking water" out of small rivers.
这项发现迫使城市官方用邻近的休斯顿湖和康罗湖代替含水土层，成为该市主要水源。
This discovery forced city officials to use nearby Lake Houston and Lake Conroe for municipal water instead of the aquifer.
这项发现迫使城市官方用邻近的休斯顿湖和康罗湖代替含水土层，成为该市主要水源。
This discovery forced city officials to use nearby Lake Houston and Lake Conroe for municipal water instead of the aquifer.
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